Level.



A. J. SKJONSBYE.

LEVEL.

APPLICATIONFILED APR-20.1917.

Patented May 14, 1918.

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LEVEL.

APPLICATION HLED APR. 20. 1917.

Patented May 14, 1918.

2 SHEETSSHEET 2.

ATTORNEY Y on.

AXEL J. SKJONSBYE, 0F BOURKES, ONTARIO, CANADA.

Specification of Letters Patent.

i LEVEL.

Application filed April 20, 1917. Serial No. 163,530.

To all wkomez't may concern:

Be it known that I, AXEL J. SKJoNsBYn, a naturalized citizen of Canada, residing at Bourkes, in the District of Temiscamingue and Province of Ontario, Canada, have invented new and useful Improvements in Levels, of which the following is a specification.

This invention relates to geometrical instriunents, and more especially to those of the straight-edge type having a protractor pivotally mounted so as to oscillate in the stock for ninety degrees; and the object of the same is to produce an improved level wherein the protraotor is normally loose on the main shaft but is capable of being fastened thereto after its oscillations cease, and finer adjustments may then be efiected by setting the shaft with respect to the stock.

Another object is to provide means for attaching an upright to the protractor in various positions, and pivoted arms on the stock which may be thrown out so that the level can be used on objects quite remote.

Further objects will be found from a close reading of the following specification and claims, reference being had to the accompanying drawings, wherein Figure 1 is a front side elevation.

Fig. 2 is a plan view with the arms thrown out in dotted lines.

Fig. 3 is a rear side elevatiomand Fig. 4 a cross section on the line 44 of Fig. 1. I

Fig. 5 is a longitudinal section, giving an elevation of the protractor,

Fig. 6 a cross section on the line 6-6 of Fig. 1, showing one of the arms thrown out in dotted lines, and

Fig. 7 a perspective detail of both arms, showing their use,

Fig. 8 is a reduced side elevation of the in strument, showing its use on an inclined member,

Figs. 9 and 10 are side elevations showing this instrument used on objects quite remote from it and having its protractor mounted on a support.

The stock 1 is preferably of skeleton formation as indicated and of course absolutely straight on its upper and lower edges and its side faces, its length and its material being unimportant, although I preferably make it of metal and about its center this stock carries a casing or housing whleh comprises a substantially semi-circular back plate 2, a marginal flange 3 pierced at its bottom with an openingt in which is set a lens 5, and a groove or channel preferably made by undercutting the inner face of the flange as seen at 6 in Fig. 2. Within said housing between the back plate and flange is disposed a semi-circular member herein called the protractor 7, its curved edge being beveled off as shown at 8 in Fig. 4. and traveling loosely within the runway 6, and the face of this beveled portion being inscribed with a scale as seen at 9 in Fig. 5 made of marks and numerals adjacent and reading from zero at the center to ninety degrees at each end thereof; and this scale is visible through the openings 4 and its marks and figures made clear to the observer by means of the lens 5. It is obvious that when the zero stands at the bottom as seen in Fig. 5, the straight upper edge of the protractor is ptarzliillel with the straight upper edge of the s cc Standing strictly parallel with such straight upper edge of the protractor, is a spirit level 10 which is rotatably mounted in bands 11 carried by the front face of the protractor. The level has a knurled operating band 12, and is preferably arranged as near the upper edge of the protraotor as possible. With the protractor very loosely mounted in the runway 6, when ltheestock is placed on an oblique member as indicated at M in Fig. 8, it is obvious that when the bubble stands at the center of the spirit level and when the protractor has ceased to oscillate, the exact angle of the said member will be visible through the lens 5 on the scale 9.

In order that the protractor may oscillate freely within the runway by its own gravity, I prefer that its beveled edge be entirely out of contact with the flange and that the body of the protractor shall be supported only on a main shaft 20 of peculiar formation yet to be explained. Referring to Fig. 4:, it will be observed that the inner end of this shaft passes through the protractor 7, and its outer portion is enlarged as at 21 and rotatably mounted in the back plate of the casing. Fast on this larger end of the shaft is a ring 22 whose aperture or eye 23 is threaded as shown, and from the ring an arm 24 projects radially. Another socket or eye 25 is formed in the straight upper edge of the protractor, usually closed by the Patented May 14., 1918.

' tight sovthat these arms as seen in full lines in Fig.

means of a plug 26; and the purpose of these eyes will be explained below. The tip of the arm 9st passes between jaws 27 on a nut '28 threaded onto a screw 29, and the latter is swiveled at its extremities 30 and 31 in an arched keeper 3:2 removably secured to the back plate by means of screws 83, the upper end of the screw having a knurled knob 34 by means of which it. may be turned.

A set screw d0 threaded into the protractor and its. knurled knob 41 preferably stands in a notch $2 in the straight edge thereof and is preventedfrom displacement by a pin -13 as seen in Fig. 1; and the tip of this screw. is adapted to beset into Contact with the main shaft 20 as seen in Fig. 5 so as to lock the protractor to the shaft. At. this time the knob is below the level of the straight upper edge of the stock as this view illustrates, so as not to interfere with the use of the instrument.

Pivotally mountedv at near each end of the stock is an arm 51 adapted to fold in under the flanged upper edge 52 of the stock 6, or to be turned outward as indicated in dotted lines in this view and as more clearly illustrated in Fig. 7. These arms are duplicates excepting that their parts are reversed as the last view shows. One of them has a sight opening or, slot 5% near its inner end and a wire 55 near its outer end, and theother has the wire 56 at the innerend of the slot 5'? at its outer end, so that one slot comes opposite the other wire. The, pivots may be rather turn outward and inward with diiiiculty, or means may be provided to hold them in either extreme positions. When not in use they are folded against thestock under its flange 52, as seen in Fig. 1.

From the above description, taken with the accompanying drawings, it will be clear that the protractor as a whole hangs pendant from the main shaft. and if the parts are well made and properly oiled the upper edge will'stand normally horizontal andits zero markv will hang directly beneath the axis of said shaft; When the stock is truly level, this zero mark will appear through the opening a. The set screw 10 may now be tightened against the shaft, and the en tire device becomes a level. To obtain the angle of anoblique member as seen at l d in Fig. 8, theset screw is loosened and the stock laid over such member. and as soon as the protractor has come to rest, the scale 9 will indicate the angle through the opening, aided by the lens. If another member is to be adjusted to the same inclination,.the set screw 40 may now be tightened against, the shaft, and the instrument can be moved to the second member and the latter adjusted to an angle corresponding to that of the first. At this time, or at any time, adjustment of the sore 29 (whose threads should be very fine) moves the nut 28 up or down, swings the arm and the ring 2:2, and turns the main shaft and with it the protractor, the latter being at this time fast on the shaft by means of the set screw e0. Thus the screw 29 and the parts associated therewith are for extremely fine adjustment as will be clear. By turning the arms 51 outward as indicated in dotted lines in Fig. 2, the user can sight through one slot. and across the opposite wire an object remote from the instrument while the latter lies on a horizon.- tal surface. In Fig. 9 I have shown how a support S mounted on a tripod T might be inserted into the socket or eye 23 in the main shaft 20, and the arms 51 raised to a vertical position so that the user could sight a verti cal line on a remote object. In Fig. 10 I have shown the same support as screwed into the socket. or eye 25 in the protractor (the plug 36 having first been removed) so that the entire instrument is reversed and the fiat edge of the stock is uppermost and the protractor is at the bottom; and the instrument may now be used in any of the ways well known to engineers and surveyors. No detailed illustration of the support is necessary, further than to suggest that its upper end should be threaded to fit the threads in the sockets or eyes. When the-instrument is reversed as seen inFig. 10, the protractor will be adjusted first as of course will be understood. All parts are of the desired proportions and materials, and further details are not essential.

What is claimed as new is 1. In an instrument ofthe class described, the combination with a stock, and arms pivotally mounted at the ends thereof and adapted to be turned outward at right angles to the length of the stock; of a pendant; element pivotally mounted at the center of the stock and having threaded sockets disposed respectively on axes parallel with its pivot and at right angles thereto, and a spirit level carried by said element for the purpose set forth.

2. In an instrument of the class described, the combination with a stock, and arms pivotally mounted at the ends thereof'and adapted to be turned outward at right angles to the length of the stock; of a pendant element pivotally mounted at the center of the stock and having threaded sockets disposed respectively on axes parallel with its pivot and at right angles thereto, a support, adapted for engagement with either of said sockets, means on said element for ascertaimng when it stands level, and means for adjusting the position of the pivot to the stock.

3. In an instrument of the class described, the combination with a stock having a sub stantially semi-circular housing at its mid- .length comprising a back plate and an inturned flange around the curved edge of said plate, the flange being pierced with an opening at its mid-length, and a lens in said opening; of a weighted element of substantially semi-circular contour, whose curved edge is movably mounted in said flange and provided with a scale passing across said opening, said element having a transverse hole concentric with its curved edge, a shaft through said hole and the back plate of the housing and means for limiting the rotation of said shaft.

4. In an instrument of the class described, the combination with a stock, a keeper thereon, a nut movable within said keeper and having spaced jaws, and a screw swiveled in said keeper and threaded through said nut; of a shaft rotatably mounted in the stock, a radial arm on the shaft projecting between the jaws of the nut, a pendant weighted element movably mounted on said shaft, and means for securing it thereto at will.

5. In an instrument of the class described,

the combination with a stock, a keeper thereon, a nut movable within said keeper and having spaced jaws, and a screw swiveled in said keeper and threaded through said nut; of a shaft rotatably mounted in the stock, a radial arm on the shaft projecting between the jaws of the nut, a pendant weighted element movably mounted on said shaft and having a notch in its periphery adjacent the same, and a set screw threaded into said element with its tip against said shaft and its head in said notch, for the purpose set forth.

6. In an instrument of the class described, the combination with a straight-edge having a bearing at its mid-length, a shaft in said bearing having a radial arm, and means for adjusting the arm and setting the shaft within said bearing; of a weighted element mounted loosely on said shaft, means for fastening it thereto when desired, and a spirit level carried by said element.

In testimony whereof I aflix my signature.

AXEL J. SKJ ON SBYE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). G. 

